For the manufacturing of jewelry and silverware, precious metals are not used in their purest forms. Instead, they are alloyed with other metals. It is not possible to discern by sight or by touch what the precious metal content of an alloy is.

In the UK, the consumer enjoys a guarantee of the precious metal content through the 700-year-old practice of an independent third party: Hallmarking.

The 1973 Hallmarking Act makes it unlawful to describe an item over a certain weight as gold, silver or platinum without an independently applied Hallmark.

• All Silver articles weighing more than 7.78 grams must be hallmarked.
• All Gold articles weighing more than 1 gram must be hallmarked.
• All Platinum articles weighing more than 0.5 grams must be hallmarked.

The “Who, What and Where” of Hallmarking:

Who

This is known as the sponsor’s mark. This mark is the registered mark of the person or company who made or submitted the items for testing and marking. In the case of Tateossian jewelry, “RT” represents the name of the designer, Robert Tateossian.

What

This mark is known as the fineness or purity mark and describes the precious metal content, expressed in parts per thousand. There is a different shaped shield for each precious
metal (see the examples below).

Where

This is known as the Assay Office Mark and tells the purchaser where the item was tested. There are four UK Assay Offices; Edinburgh, London, Sheffield and Birmingham.